Multiple speed transmission



March 14, 1961v E. R. DAvlEs ET AI MULTIPLE SPEED TRANSMISSION 10Sheets-Sheet l Filed Dec. l0, 1953 QM Nwm wwm wwm w March 14, 1961 FiledDec. l0, 1955 E. R. DAVIES ET AL MULTIPLE SPEED TRANSMISSION l0Sheets-Sheet 2 EEB EED-

ZZOU Z600 3000 EEC INVENToRs: Edward R. Davies Glenn L. Bowen BY RobertW. Lemon TTORN E Y.

March 14, 1961 E. R. DAvlEs ET AL 2,974,545

MULTIPLE SPEED TRANSMISSION Filed Dec. 10. 1955 l0 Sheets-Sheet 3INVENTOES: Edward R. Davies BY l Glenn L. Bowen Robert W. Lemon @wwfATTORNEY.

March 14, 1961 E. R. DAv|Es ET AL MULTIPLE SPEED TRANSMISSION 10Sheets-Sheet 4 Filed D90. 10, 1953 wmv @Sv www www 3v MMS www Www. WM SvNnsw R5: Edward R. Davies Glenn L. Bowen SSM/lm Robert W. LemonATTORNEY.

March 14, 1961 E. R. DAvlEs ETAL MULTIPLE SPEED TRANSMISSION l0Sheets-Sheet 5 Filed Deo. 10. 1955" Whg Y* 1NVENTOR. S= Edward R. DaviesBY Glenn L. Bowen Robert W. Lemon MJ ATTORNEY.

March 14, 1961 E. R. DAvlEs ET AL 2,974,545

MULTIPLE SPEED TRANSMISSION Filed DeG. l0, 1955 l0 Sheets-Sheet 6 EdwardR. Davie BY Glenn L. Bowen Robert W. Lemon ATTORN E Y.

March 14, 1961 E. R. DAvlr-:s ETAL MULTIPLE SPEED TRANSMISSION FiledDec. 1o. 195s l0 Sheets-Sheet 7 Edward R. Davis Glenn L. Bowen BY RobertW. Lemon wjm ATTORNEY.

March 14, 1961 E. R. DAvlr-:s ETAL 2,974,545

MULTIPLE SPEED TRANSMISSION Filed Dec. l0, 1955 10 Sheets-Sheet \/IINVENToR:

Edward R. Dawes www ATTORNEY.

E. R. DAvlEs ET AL 2,974,545

MULTIPLE SPEED TRANSMISSION March 14, 1961 Filed Dec. 10, 1953 l0Sheets-Sheet 9 .ff/ff l u ENToRs: Edward R. Davies BY Glenn L. BowenRobert W. Lemon ATTORNEY.

10 Sheets-Sheet 10 www www www .www .mv v NS Sv w Nb QN .DAEmMIMIHHI wwww INVENToRs:

Edward R. Davies Glenn L. Bowen BY Robert w. Lemon ATTORNEY.

March 14, 1961 E. R. DAvlEs ET AL MULTIPLE SPEED TRANSMISSION Filed Dec.10, 1953 v- States 2,974,545 MULTIPLE Srnnn TRANSMISSION This inventionrelates to a power transmitting mechanism and more particularly to avariable speed transmission of the planetary type which is especiallyadapted for use with heavy wheeled or tracked vehicles and powerequipment or the like, but which is also capable of other uses.

The provision of a transmission of the type brietly mentioned abovebeing the principal object of the invention, another object of theinvention is to provide a power transmission having a power outputShaft, a power input shaft and a plurality of planetary gearsets foroperatively interconnecting the power output and power input shafts toprovide selectively a series of speed reduction ratios.

Another object of the present invention is to provide a powertransmission which includes a series of compounded planetary gearsetsand clutch and brake means for selectively controlling the individualelements of each planetary set in an operative sequence to obtain aseries of reduction ratios which are evenly stepped from the lowest tothe highest ratio. l

Another object of the present invention is to provide a powertransmission having a plurality of planetary gearsets assembled andcompounded into a compact arrangement having minimum space requirements.

Another object of the present invention is to provide a powertransmission having a power input shaft, a power output shaft, a seriesof compounded planetary gearsets for operatively interconnecting theinput and output shafts, clutch and brake means for selectivelycontrolling the component elements of each planetary set, and a simpleplanetary gearset operatively interposed between the input shaft and theseries of compounded planetary gearsets.

Another object of the present invention is to provide a powertransmission mechanism according to the preceding object wherein thesimple planetary set is operative to provide alternately two reductionratios which are selectively combined with the reduction ratios obtainedin the series of compounded planetary gearsets.

Another object of the present invention is to provide a powertransmitting mechanism according to the preceding object in which thesimple planetary gearset is adapted to provide alternately two gearreduction ratios for each of the reduction ratios obtained in the seriesof compound planetary gearsets thereby providing a number of overallreduction steps which is equal to twice the number of steps obtainablein the series of compound planetary sets when used alone.

Another object of the present invention is to provide a powertransmitting mechanism for delivering power from a power input shaft toa perpendicular power output shaft which includes a series of compoundedplanetary gearsets and an independent planetary gear unit, the poweroutput element of the independent gear unit being connected operativelyand drivingly to the compounded planetary sets by suitable gear means,the elements of the compounded-gearsets being selectively con- .powerfrom any suitable power source.

. 2,974,545 Patented Mar. 14, 1961 trolled by clutch and brake means,and the elements of the independent planetary unit being controlledselectively and alternately to provide a plurality of overall reductionratios for each reduction ratio of the compounded planetary elements.

Another object of the invention is to provide a new and improvedmultiple speed transmission having a plurality of evenly stepped overallreduction ratios in a forward direction and also a full range of reversespeeds.

Another object of the invention is to provide a transmission having anew and improved arrangement of planetary gear elements.

Another object of the invention is to provide a drive transmittingmechanism having new and improved suhassemblies of planetary geartrains.

Other objects and advantages of the invention will become apparent fromthe following description and the accompanying drawings wherein:

Figure l is an assembly view of the multiple speed transmission;

Figure 2a is a plot of the performance characteristics for a typicalembodiment of the present invention;

Figures 2b and 2c are a plot of the engine characteristics for a typicalengine used to obtain the curves of Figure 2a;

Figure 2d is a schematic representation of the components for a typicalvehicle installation incorporating the transmission of the subjectinvention together with auxiliary reduction units;

Figures 3 through 10 are valving diagrams for one suitable automaticcontrol means for the transmission of the present invention, each viewshowing the operative positions of the valves for separate transmissionspeeds.

In setting forth the principles of the invention, reference will be madeto'one particular embodiment herein disclosed in which fourinterdependent planetary gearsets are concentrically disposed about anoutput shaft. These gearsets are grouped into two pairs spaced axiallyalong the output shaft, each set comprising a ring gear, a set of planetgears with a carrier, and a sun gear. The two sun gears for each pair ofgearsets are integrally assembled upon common shafts which areconcentrically disposed with respect to each other, the sun gears of onepair being clutched to a power input source, and the sun gears of theother pair being splined to the output shaft.

SuitableV brake means are provided for selectively braking the ringgears of the one pair of gearsets, and the carrier of the rst of thispair of gearsets is operatively connected to the ring gear of the secondof the pair. The carrier for this second of the one'pair of gearsets issplined tothe output shaft.

`The sun gears for the one pair of gearsets are operatively connected tothe carrier of a rst of the other pair of gearsets by means of a hollow,axially extending shaft concentrically disposed about the output shaft.The ring gear for this iirst of the other pair of gemsets is operativelyconnected to the carrier for the second of the other pair. Means areprovided for selectively braking the ring gear for this second gearsetand for clutching the same to the output shaft.

The power input source for the above-described four interdependentplanetary gearsets includes an input shaft disposed perpendicularly tothe output shaft, said input and output shafts being drivably connectedby a suitable bevel gear drive. This input shaft is splined yto thecarrier assembly of a simple planetary gear unit which will hereinafterbe referred to as the Split ratio unit. The ring gear of the split ratiounit is adapted to receive Means are provided for selectively andalternately clutching the sun gear of the split ratio unit to thecarrier and input shaft and for braking the sun gear to the transmissioncasing.

Suitable control means may be provided for progressively clutching andbraking the component elements of the four interdependent and compoundedplanetary gearsets and for alternately clutching and braking the sungear of the split ratio unit as previously pointed out. For purposes ofthe present disclosure the term compounded planetary gear unit orgearset will be used to describe a gear unit which cooperates withanother gear unit in such a way that the two units produce a combinedgear ratio. When so used, the term compounded gear unit may be used todescribe cooperating gear units capable of producing a torque split orcapable of combining torque from separate paths and distributing thesame to a unitary torque delivery path.

The clutches or brakes for the four compounded planetary gearsets may beindividually energized in an operative sequence, and as each clutch orbrake is so energized, an additional speed ratio may be obtained merelyby alternately clutching and braking the sun gear of the split ratiounit. Thus, the split ratio unit is effective to double the number ofspeeds which might ordinarily be obtained from the four compoundedplanetary gearsets alone.

:For the purpose of more particularly describing the presently disclosedembodiment, reference will rst be made to the assembly view of Figure 1wherein the numeral is used to generally designate the transmissionproper, and the numeral 12 is used to designate the split ratio unit.The transmission housing casting is shown at 14 and is substantiallycylindrical in shape. An end plate 16 is suitably secured to one end ofthe housing 14 as shown. The plate 16 is provided with a suitableaperture 1S adapted to receive a bearing 20 which rotatably secures apower output flange 22. A suitable bearing retainer and a seal areprovided at 24 and 26 respectively.

The flange 22 is splined at 28 to a hub extension 30 of a planet carrier32. The hub extension is in turn splined at 34 to a power output shaft36 which extends axially thrrough the housing 14. The carrier 32rotatably carries upon needle bearings 37 a plurality of planet gears 38which are engaged with ring gear 40.

The ring gear 40 is supported and positioned by members 42 which extendradially inward from ring gear 40 and which are rotatably journalled bybearing 44. The bearing 44 is seated upon the hub extension 30.

The outer periphery of the ring gear 40 is provided with splines at 46which receive a plurality of internally splined brake discs 48.Stationary discs 50 are alternately interposed between the discs 48, asshown in Figure 1, and are fixed to the housing 14 by means of an anchormember or key 52.

An annular piston member is shown in Figure 1 at 54 and is adapted tomove axially within an annular cylinder defined by the plate 16 and ringmember S6, the latter being secured to the plate 16 concentrically withrespect to shaft 36 and ring gear 40. Suitable piston rings 5S and 60may be provided on the ring member 56 and piston 54 respectively.

The piston member 54 is actuated by hydraulic fluid which enters asuitable port 62 and then progresses throughout a circular recess 64 incover 16. The hydraulic fluid is thereby caused to act against thepiston 54 and move the same axially thereby causing the discs 48 and S0to be compressed between housing 14 and the piston 54.

The ring gear 40 is integrally joined to the carrier 66 of a secondplanetary set by means of extension 68. The carrier 66 rotatably mountsa plurality of planet gears 70 by means of needle bearings 72. Theplanet gears 70 engage a ring gear 74 which is externally splined at 76and which carries brake discs 78 about the periphery thereof.

Mating brake discs 80 are alternately disposed with respect to the discs78 and are retained in a xed position by an anchor member 82.

The anchor member 82 also retains a circular servo cylinder member 84 ina xed position, as shown in Figure l. A corresponding circular pistonmember 86 is siidably received within the cylinder member 84 and isadapted to move axially against the discs 78 and 80 when hydraulic iluidis supplied under pressure to the port 88 thereby compressing the discs78 and 80 against the housing 14. The hydraulic actuating uid enteringport 88 is allowed to become distributed over the lateral working face90 of piston member 86. Piston rings 92 are provided as shown forsealing purposes.

The sun gears for the planet sets previously described are shown at 94and 96, respectively, and are formed integrally upon a common sleeve 98which is splined to a sleeve concentrically disposed about the poweroutput shaft 36.

A clutch member 102 is also splined to the sleeve 100 and it extendsradially to a set of clutch plates 104 which are internally splined uponthe periphery of the member 102. The clutch plates 104 are alternatelydisposed with respect to plates 106 which are carried by clutch member108 which in turn is splined at 110 to a hub extension 112 of bevel gear114.

rFhe clutch member 108 is provided with an annular recess 116 withinwhich a servo piston member 118 is slidably received. Hydraulicactuating uid is admitted to the working surface 120 of piston 118through a port 122 thereby causing the plates 104 and 106 to becompressed against the abutment portion 124 of the clutch member 108.The actuating fluid is transmitted to the port 122 through the annularspace surrounding sleeve 100 and the uid passage 123 which is adapted toreceive an external uid connection extending from a control valve bodysubsequently to be described. Sleeve bearings are provided at 126 and128 to provide needed support for the clutch member 102 and carrier 66respectively.

The brake 48, 50, the brake 78, S0 and the clutch 104, 106 are eachprovided with a spring return means at 130, 132 and 134, respectively,for disengaging the associated clutch or brake when the hydraulicactuating pressure is released.

The bevel gear 114 and the associated hub extension 112 are rotatablyjournalled about shaft 36 by means of bearing 136 which is retainedwithin an adaptor plate 138 secured to the inwardly extending ange 140of housing 14. The bevel gear 114 is also rotatably mounted by means ofbearing 142 within a fixed yoke extension 144 of the housing 14.Suitable rib members, not shown, may be used to support the structure144 and secure the same to the housing 14.

Another bevel gear 146 is drivably engaged with the gear 114 fand isprovided with a hub 148 which is rotatably mounted within the yokestructure 144 by means of a suitable bearing 150. The gear 146 hasanother hub extension 152 which is rotatably journalled in bearing 154secured and retained within a mounting plate 156 which in turn is boltedto the casing 14 4at 158.

The hub extension 152 is internally splined at 160 to receive the shaft162 of the split ratio unit 12. The shaft 162 is splined at 164 to aclutch member 166 which extends radially from the shaft 162 to which itis integrally splined. The outer periphery of the radially extendingmember 166 is splined to receive internally splined clutch plates 168. Amating set of clutch plates 170 are alternately disposed in matingrelationship with respect to plates 168 and are drivably carried by theclutch and brake member 172 which is rotatably mounted about shaft 162and which also carries brake disc 174- ab-out the outer peripherythereof.

The disc 174 is disposed adjacent the discs 176 which are held in afixed position by anchor member 178 which is retained in the outercasing for the split ratio unit 12. An annular ring 180 is secured tothe housing 14 and serves as a servo cylinder for the brake assembly174, 176. A circular piston member 182 is received Within ring 180 andis adapted to be moved in the direction of the axis of shaft 162 bymeans of hydraulic uid which is permitted to enter port 184. The Workingsurface 186 of the piston member 182 is in communication with the port184. Upon movement of the piston 182, t-he discs 174 and 176 arecompressed against the` abutment member 188 secured to the outer casingof the split ratio unit.

The clutch and brake member 172 is provided with Ian annular recess 190Within which a circular piston 192 is slidably retained. The piston 192has a radial portion 194 which acts against the clutch plates 168 and170 to compress the same against an extension 196 of the hub of sun gear198. Extension 196 and the clutch and brake member 172 are integrallyjoined at 200 thereby forming one integral unit. The piston member 192is 'actuated by hydraulic fluid which enters conduit 202 and which thenis allowed to pass through conduit 204 and port 206 into the workingchamber behind the working face 208 of piston 192. A suitable returnspring means is provided as shown for returning the piston 192 to theinoperative position when the hydraulic actuating pressure is reduced. Asimilar return spring means may also be provided to similarly return thepiston 182 to the inoperative position.

lA carrier member for the split ratio unit 12 yis shown at 214 and isintegrally splined to the shaft 162 at 164 along with the member 166forming an integral assembly with the same. Planet gears 216 arerotatably mounted on carrier member 214 upon needle bearings 218 andthey mesh with the sun gear 198 and the associated ring gear 220. Thering gear is drivably secured to a power input shaft 222 by means of aradially extending iiange 224 on the shaft 222.

The shaft 222 is rotatably journalled in the outer housing for the splitratio unit 12 by means of suitable bearings 226 and 228. A power inputBange 230 is integrally splined to shaft 222, as shown at 232.

Suitable bushings may be provided as needed port at 234, 236, 238, and240. u

Referring again to the yoke structure 144 of Figmre l, it is seen that asecond bevel gear 242 is mounted therein in juxtaposed relationship withrespect to bevel gear 114. A suitable bearing is provided at 244 forthis purpose between the hub of gear 242 and the structure 144.

An adaptor plate 246, which corresponds to the previously describedplate 138, is bolted to an inwardly extending fiange 248 of the housing14 and serves as a mounting member for bearing 250 which is seated upona hub extension 252 for the gear 242 and which supports the same.

A clutch member 254 is splined at 256 to the hub extension 252 and itcomprises a radially extending portion which carries an internallysplined adaptor 258 at the radial extremity thereof. A series ofexternally splined clutch plates 268 are received Within the adaptor258.

A carrier member 262 for another planetary gearset is shown in 'Figureland it carries a clutch member 264 which is integrally secured thereto.The periphery of the clutch member is externally splined to carry theinternally splined clutch plates 266 which are alternately disposedinadjacent relationship with respect to plates 260.

The member 254 is formed with an annular recess 268 which receives anannular piston member 278. The piston member 270 is formed with a radialportion 272 which is adapted to engage the clutch plate assembly 268,266 and compress the same against a shoulder 274 secured to the member254 and adaptor 258. Axial movement of the piston 270 takes place ashydraulic fluid is admitted under pressure through port 276 into theworking space beh-ind the piston face 278. A suitable return springmeans providedas shown, is operative to return ,the piston 270 to forVsup- 6 an inoperative position when the hydraulic Working uid isexhausted from annular recess 268.

The carrier member 262 is integrally splined to the sleeve 108 at 282and it carries planet gears 284 which engage an associated ring gear286.

The ring gear 286 is supported by an extension 288 on the planet carriermember 290 which is in turn rotatably mounted by means of bearing 297and bushing 294.

The carrier 290 rotatably carries a plurality of planet gears 296 whichengage their associated ring gear 298. The ring gear 298 is provided'with a radially extending brake -disc 388 which is interposed betweenfriction discs 382. An annular ring, which defines in part a servocylinder, is provided at 304 and is integrally secured to housing 14. Acircular piston member 306 is slidably received within the ring 304 andis adapted to move axially as hydraulic iiuid is admitted under pressurethrough port 388 thereby compressing the disc 300 yand 302 against ashoulder 310 secured to the housing 14.

The ring gear 298 is also provided with a radially extending clutchplate 312 in the side opposite to that which carries disc 388. The plate312 is disposed between plates 314 which are drivably carried by thereaction member 316 which in turn is splined at 318 to the shaft 36.

The reaction member 316 is provided with an annular recess 328 whichreceives piston member 322 having a radial portion 324 which is adaptedto engage the clutch plates 312 and 314 and compress the same againstthe shoulder 326 formed on the reaction member 316. Actuating uid may beadmitted to the working space behind the piston 322 through port 328 tomove the piston axially against the clutch plates 312 and 314.

The sun gears for the pair of compounded planet sets just described areshown at 330 and 332 respectively. Each of these sun gears is integrallysplined to the shaft 36 at 334 and 336, respectively.

A second power output flange 338 is splined to the shaft 36 at 34@ andis rotatably -supported within a closure plate 342 by means of asuitable bearing 344. Closure plate 342, which corresponds to-plate 16at the opposite end of the shaft 36, is integrally secured to thehousing 14.

In describing the operation of the present invention and the sequencerequired in energizing .the various clutches and brakes to selectivelyobtain steps of progressively increasing speed ratios, the followingnomenclature will be used for purposes of clarity.

'Brake assembly 174, 176=brake l Brake assembly 48, 50=brake 2 Brakeassembly 78, =brake 3 Brake assembly 300, 302=brake 4 Clutch assembly168, 170=clutch l Clutch assembly 312, 314=clutch 2 Clutch assembly 260,266=forward clutch `Clutch assembly 104, 106=reverse clutch First'speedforward opel'ation--engage-forward clutch, brake 1 and brake 2 Power isdelivered to the input flange 230 which drives the shaft 222 and ringgear 220. The sun gear is held against rotation, the :torque reactionbeing taken by brake 1, and the planet carrier 214 drives shaft 162 andgear 146 at a reduced speed. The power is delivered to gear 242 whichtransfers it to carrier 262 through the forward clutch. Carrier 262drives sleeve which drives sun gear 94. The ring gear 4t) associatedwith sun gear 94 is held stationary by brake 2 and the carrier 32 isthereby driven at a further reduced speed which in turn drives the shaft36 and the output flanges 22 and 338.

Second speed forward operation-engage-forward clutch, clutch 1 and brake2 The power is again delivered to shaft 222 through ange 231). Theclutch l is effective to lock the sun gear 198 to the shaft 162. rlhusboth the carrier 214 and the sungear 198 are locked to the same member,

7 namely, shaft 162. Therefore when the shaft 222 drives the ring gear220, the entire planetary assembly will turn as a unit at a l to 1ratio. The power flow path from the shaft 162 to the output flanges 22and 338 will be the same as that previously described for first speedoperation.

Third speed forward operation-engage-forward clutch, brake 1 and brake 2The power delivered to input shaft 222 and flange 230 is again deliveredto shaft 162 at a reduced speed ratio since the sun gear 198 is nowbraked against the casing and the carrier 214 is directly connected toshaft 162. Shaft 162 drives bevel gear 146 which drives bevel gear 242.Power is delivered from gear 242 to sleeve 160 through the forwardclutch and carrier 262. The sleeve 100 is effective to drive both sungears 94 and 96. Since the ring gear 74 is held by brake 3, the planetcarrier drives the ring gear 40 in the same direction as the directionof rotation of sun gear 94 but at a lesser speed. There is, therefore, asplit path for the flow of power from the sleeve. 100 to the outputcarrier through the compounded planetary sets. The carrier 32 isintegrally splined to the output shaft 36 and output flange 22.

Fourth speed forward operation-engage-forward clutch, clutch 1 and brake2 It is seen that in order to shift from third to fourth speed, it isnot necessary to change the power ilow path through the compoundedplanet sets. The only change required is to cause. brake 1 to becomedisengaged and clutch l to become engaged. This creates a l to l ratiobetween the speed of shaft 222 and shaft 162 which, when combined withthe speed ratio already existing in the compound planet sets, willresult in a higher overall speed ratio.

Fifth speed forward operationengage-forward clutch, brake l and clutch 2The power input to flange 230 is again operative to drive shaft 222 andring gear 220 which, by virtue of the -fact that the sun gear 198 isbraked to the casing, causes the carrier 214 and shaft 162 to turn at areduced speed ratio. The shaft 162 is again effective to drive gear 146which powers gear 242. Power is again delivered to the carrier 262through the forward clutch. Clutch 2, in effect, locks the ring gear 298to shaft 36. Since both sun gears 330 and 332 of the second set ofcompounded planet gears now being considered are also locked or splinedto shaft 36, the entire compound planetary assembly turns as a unit at areduction ratio Thus the overall speed ratio under this condition isequal to the speed ratio of the planetary set in the split ratio unittimes the ratio produced by the bevel gears 146 and 242.

Sixth speed forward operation-engage-forward clutch, clutch 1 and clutch2 To obtain sixth speed, the compounded planetary ratios remainunchanged and the sun gear 198 and carrier 214 in the split ratio unitare again locked together by clutch 1 thereby producing a 1 to l ratiobetween input shaft 222 and shaft 162. This l to l ratio in the splitratio unit, when combined with the similar ratio in the compoundedplanetary sets, results in an overall speed ratio, that is equal to theratio produced by bevel gears 146 and 242 which, in this particularembodiment, is 1.182 to 1.

Seventh speed forward operationengage-forward clutch, brake 1 and brake4 The power delivered to gear 146 by the split ratio unit is transferredto bevel gear 242 and then to carrier 262 through the forward clutch.Since the sun gear 330 is splined to the output shaft 36, the ring gear286 of speed. Since the ring gear 298 is held, the net result will be anoverspeeding of the sun gear 332 and hence the output shaft 36.

Eighth speed forward operaton-enage-forward clutch, clutch I and brake 4To obtain eighth speed it is only necessary to release brake 1 andengage clutch 1 in the split ratiounit thereby obtaining a 1 to l ratioin the split ratio unit which, Iwhen combined with the overspeedingratio of the compounded planetary sets, results in the highest overallspeed ratio.

To obtain reverse operation, the same sequence of steps may be followedexcept that the reverse clutch will be engaged at all times while theforward clutch is released. Tinus it is possible to obtain the sameratios over the entire speed range for reverse as well as for forwardoperation.

By way of summarizing the above-described sequence of operation, thefollowing tables are provided together' with a tabulation of typicaltorque multiplication ratios which may be obtained with the presentembodiment of the invention. These figures are intended to beillustrative of the overall reduction ratios which are obtainable andare not of a limiting nature.

FORWARD OPERATION Speed Energize Ratio REVERSE OPERATION Speed EnergizeRatio For the purpose of graphically illustrating the performancecharacteristics for the present embodiment of the invention, the chartsof Figure 2a are provided. These performance curves were computed for atypical tracked vehicle weighing approximately 12.5 tons per track andhaving an air-cooled engine with a speedtorque characteristic and aspeed-BH1. characteristic las shown in Figures 2b and 2c respectively.It has been assumed that the present transmission has been installed ina tracked vehicle installation which also includes a first reductiongear unit having a constant speed ratio of 6.05 to l and a secondtwo-Speed reduction unit or final drive having a low speed ratio of 2.95to l at each output flange to further increase the output torque and totransfer the same to the vehicle sprocket wheel which are normallydisposed below the centerline of the output shaft. The pitch diameter ofthe sprocket wheels was assumed to be 33.335 inches. The dotted linecurves in Fig. 2a represent the performance when the final drive is inthe lowest ratio.

The rolling resistance was assumed to be 140 lbs. per ton and this valueis represented by a horizontal line in Fig. 2a.

A schematic diagram showing the relative position of the variouscomponents of the typical arrangement above described is illustratedschematically in Figure 2d. The vehicle engine is shown by means of thesymbol E. The output of the engine is delivered to the multiple tends tooverspeed and drive carrier 290 at the same rate Speed transmission ofthe present invention shown at T.

9 The output anges of the transmission T extend transversely to eitherside of the vehicle to the above-mentioned first reduction gear unitshown at R1. The output of the reduction unit R1 is transferred to thetwo-speed final drive unit designated by the symbol R2, which has a lowspeed reduction ratio of 2.95 to 1 as above mentioned. The output of thetwo-speed final drive R2 is connected to the sprocket wheel for thevehicle.

Identical reduction units are provided at each side of the transmissionT. The two-speed final drives R2 enablethe operator of the trackedvehicle to accomplish turning maneuvers.

An `automatic control valve arrangement suitable for use in controllingand sequentially energizing the clutch and brake servos of the presenttransmission is illustrated schematically in Figures 3 through 10. Thisarrangement will be described for the purpose of providing a morecomplete understanding of the operation of the transmission. It isrepresentative of one of several types of automatic shift controlmechanisms which may be employed.

Referring first to Figure 3, a gear pump type governor is shown at 400having a driving gear 402 and an idler gear 404. The gear 402 may bedriven by drivably connecting the same to a suitable driving gearpowered by the output shaft 36 thereby causing the pump speed to bedirectly proportional in magnitude to the speed of the power `outputflanges of the transmission,

A high pressure discharge conduit 406 extends from the discharge side ofgear pump 402, 404 and communicates with conduit 488 which extends toone end of a governor valve 410. A low pressure intake conduit 412communicates with an exhaust port shown at 414.

A governor control valve is shown at 416 and it is effective toalternately connect the conduit 406 to either the exhaust port 414 orthe conduit 408 while simultaneously alternately connecting the conduit412 to either the conduit 408 or the port 414, respectively, dependingupon the axial position which is assumed by the valve 416.

The valve 416 is actuated by a rod 418 which is linked to another rod420 by a suitable bell crank 422. Rod 420 is operatively connected to acrank 424, which is centrally pivoted at 426 and joined to a selectorvalve 428. A spring loaded detent 430 is effective to maintain the valve428 in either of three axial positions depending upon whether thetransmission is to be shifted into forward drive, reverse drive or intoneutral.

A suitable means may be provided for manually shifting the rods 418 and420 to selectively obtain forward and reverse speeds. In the positionsshown in Figure 3 the valves are adapted for forward speed operation.

It is apparent that the rotation of the gear pump 402, 404 will bereversed when the transmission is operated in reverse rather than inforward speed. The valve 416 will, however, prevent the high pressurefluid from being exhausted out of the port 414 since it is shifted in anaxail direction upon movement of the valve 428 and rods 418 and 420 toconnect the opposite sides of the pump to the line 408 and to exhaustport 114, respectively.

The governor valve 410 comprises `a hollow cylindrical body 430 having afixed inner sleeve 432 which slidably receives the piston-like member434. A plunger 435, having valve surfaces thereon, is adapted to controlthe member 434 and to be axially moved thereby within an extreme end ofthe body 430.

A low pressure exhaust cavity 438 surrounds one portion of sleeve 432within the body 430, and communicates with a series of axially spaced ipjets 440 in the piston-like member 434 by means of port 442 formed inthe sleeve 432. A series of progressive jets 431 are provided in sleeve432 and they communicate, as shown, with cavity 438.

The structural details of the various valve components will becomeapparent from the following -description of the operating sequence overthe full range of shifts. For purposes of simplifying the description,it will be assumed that the engine is kept at a constant throttleposition and that the speed of the vehicle is progressively increasedfrom the lowest to the highest value. Also, it will be assumed that thetransmission remains in forward speed operation.

First speed operationrefer to Figure 3 The high pressure governor oil isdelivered to one side of piston 434 and moves the same in an axialdirection against the balancing force exerted by spring 444, the plunger435 being moved along with piston 434 by virtue of the abutting contacttherebetween. A throttle modulated pressure exists in chamber 446 whichserves to supplement the force exerted by spring 444 upon piston 434.

A conduit 448 extends from the chamber 446 through a manual lock-downvalve shown at 450, which will subsequently be described more fully. Theconduit 448 finally extends to a throttle modulating valve 452 fromwhich it receives a supply of fluid at a modulated pressure determinedby the position of the engine throttle linkage shown in part at 454.

The piston 434 moves to the position shown in Figure 3 wherein the ipjet A is in communication with the ports 442. The restriction offered bythe port 442 to the passage of duid from the governor valve to theexhaust conduit 'shown at 456 is such that the piston 434 may bestabilized in one axial positionfor a given governor pump outputpressure which in turn is proportional to engine speed. A high pressuresupply line is shown at 458 which may contain liuid under a pressure ofapproximately 200 p.s.i. The line 458 may be connected to any suitablepump source.

The high pressure uid from the supply line 458 is applied directly tothe forward clutch by means of the conduit 460 which extends to theforward clutch through a transmission clutch relay valve shown at 462and the selector valve 428.

The clutch relay valve 462 is effective to control the distribution ofsupply line pressure to either the forward or reverse clutches and itincludes a sliding element 464 which is moved by a manually actuatedcrank 466 against the force of spring 468. When the crank 466 isretracted manually, the valve element blocks the conduit 460 to preventthe forward or reverse clutch from being energized. As the crank 466 isslowly returned toward the position shown, the valve element 464 effectsa gradual pressure build-up in the forward or reverse clutch servo togradually energize the same.

The selector valve 428 is effective to selectively energize either theforward or reverse clutches depending upon the position of a slidingvalve element 470. The various positions of element 470 may be fixed bythe valve elements 470 shown at 472. When the detent means assumes thecentral position, supply fluid pressure is blocked from reaching boththe reverse and forward clutches and the transimission is then said tobe in neutral.

Another conduit, shown at 474, is connected to the supply line 458through a regulating valve 476. The pressure within conduit 474 isv at areduced pressure, approximately 70 p.s.i., and is represented by meansof crossed shading marks while the supply pressure in line 458 isrepresented by horizontal shading marks.

The conduit 474 extends to the governor valve 410 and is connected toconduit 478 by means of the ports 480 and 482 formed in sleeve 436. Theplunger 435 has spaced lands thereon at 484 and 486 which serve todirect the fluid under pressure from port 480 to conduit 478 through anannular space formed between the plunger 435 and sleeve 436.

The conduit 478 extends to the split ratio shift valve shown at 488. Theregulated pressure in conduit 474 is permitted to act against one end ofa movable element 490 and moves the same axially against the pressureexerted thereon by spring 492.

When the element 490 is in the position shown, communication isestablished between another conduit shown at 494 and the brake B1 in thesplit ratio unit and cornmunication is blocked between clutch C1 andconduit 494.

A pressure modulating valve is shown at 496 which is adapted tointerconnect the supply conduit 458 and the conduit 494 and to modulatethe supply pressure in response to the movement of the throttle linkageportion 454. The modulated pressure, which is shown by means of dottedshading, is applied to the brake B1, as shown, and to the main relayvalve shown at 49S through the branch conduit 500.

The `main relay valve 498 comprises three separate, abutting, slidingelements, 502, 504, and 506. The element 502 is hollow, and in theposition shown in Figure 3 it is effective to establish communicationbetween the brake servo B2 and conduit 500 thereby causing the brakeservo B2 to be energized with throttle modulated oil pressure. A spring508 is effective to bias the elements S62, 504 and 506 in one axialdirection.

Since both brake servo B1 and the brake servo B2 are energized, thetransmission will operate in the rst speed range.

Second speed operationrefer to Figure 4 Referring next to Figure 4, theposition of the various valve elements there shown is that which existsduring second speed operation. Upon an increase in engine speed thegovernor oil pressure in conduit 408 is increased. Accordingly, thepiston 434 may now move axially against the force of spring 444 and thethrottle modulated pressure until the port B in the piston 434 isdirectly over the port 442. The first progressive jet 431 is alsouncovered thereby increasing the total exhaust area for the governorpump discharge pressure. This axial movement of the piston 434 isaccompanied by a corresponding movement of the land 486 on the plunger435 which causes the same to block off the conduit 478 from conduit 473which contains regulated uid pressure from line 458. Simultaneously, theconduit 474 is opened to the exhaust conduit 456 through the ports 482.

Accordingly, the regulated pressure acting against the plunger 490 inthe split ratio shift valve 488 is reduced and the spring 492 is noweffective to shift plunger 490 to the right as shown in Figure 4 therebycausing the modulated fluid pressure in conduit 494 to be blocked offfrom brake servo B1 and to be simultaneously applied to clutch servo C1.

It should be noted that the modulated pressure in conduit 494 and branchconduit 500 is still continuously applied to the brake servo B2 throughthe main relay valve 498. Thus brake servos B1 and B2 are energizedwhich will result in second speed operation as previously explained.

Third speed operation-refer to Figure 5 Upon a further increase in thespeed of the governor pump 400 as the vehicle speed increases, thegovernor pressure in conduit 408 may be suicient to move the piston 434axially from the position shown in Figure 4 to that shown in Figure 5until the port C in piston 434 assumes a position directly over theports442, said movement taking place against the opposing force ofspring 444 and the opposing force due to the throttle modulated pressurein chamber 446. The second progressive jet 431 is simultaneouslyuncovered thereby further increasing the governor pressure exhaust area.This movement causes the valve land 486 to move further to the right, asshown in Figure 5 thereby once again permitting regulated pressure toenter conduit 478 through the annular space provided between land 436anda second land onplunger 475 shown at 512. The regulated pressure inconduit 478 is again effective to'act against plunger 490 which, aspreviously seen, causes the same to shift against the biasing force ofspring 492 to permit modulated pressure to energize brake servo B1 Whilesimultaneously exhausting the clutch servo C1.

It will further be noted that the valve land 484 has moved sufficientlyto the right, as viewed in Figure 5, to provide uid communicationbetween conduit 474 and a conduit 514 which extends to one side ofslidable valve element 506 in the main relay valve 498. The reguiatedpressure thus transmitted to the relay valve 498 causes the elements506, 504, and S02 to shift against the biasing force of spring 508 untilthe valve element 506 contacts a shoulder 516 in the main relay valve498. This movement of valve element 502 causes the valve lands S18 and520, which are formed thereon, to block off the conduit extending fromrelay valve 498 to brake servo B2 and to simultaneously cause the branchconduit S98 to be in fluid communication, through the axial passagewayprovided as shown through the center of the element 502, with the uidconduit which extends to brake servo B3. The brake servo B2 is exhaustedthrough exhaust port 522.

A split ratio exhaust control valve is shown at 524 and it includes aplunger 526 which is actuated by a linkage mechanism shown at 528 and530. As seen from the drawings, the linkage mechanism 528, 530 iseffective to shift the plunger 526 to the right as the valve element S02moves to the left. The axial position of the plunger 526 is positivelydetermined by a suitable spring-loaded detent means shown at 532.

After the main relay valve has assumed any of the several operativepositions, the clutch C1 may be exhausted through the annular spaceprovided between any two adjacent valve lands of a series of such landsprovided on plunger 526 and then through the exhaust port 534. Inshifting from the position shown in Figure 4 for second speed operationto that shown in Figure 5 for third speed operation, the plunger 526 ismoved to the right so that the fluid in clutch servo C1 may exhaustthrough theunnularspace provided between the first two of the series ofvalve lands which are designated by numerals 536 and 538. During thetime interval which elapses while valve element 502 and plunger 526 arein motion, the exhaust conduit for clutch servo C1 is blocked olf by thevalve lands 536 and 538 so that the only means for the escape of theenergizing fluid from clutch servo C1 is that which is provided by arestricted orifice shown at 540 inthe exhaust conduit. The action of theplunger 526 is thus effective to cause a slight delay after the shiftfrom second speed to third speed is initiated and it insures that theclutch servo C1 will not be fully deenergized before the brake servo B3is fully energized. This overlapping in the shifting sequence willassure a smooth shift and the associated planetary elements will not bemomentarily speedcd up or caused to run-away.

It is also apparent from the drawings that the modulated pressure inconduit 514 is transmitted to the spring chamber for'the relay valve 462during operation in third speed range or in any higher speed range toresist manual declutching of the forward or the reverse clutch.

Thus brake servos B1 and B3 are now energized which results in thirdspeed operation as previously described.

Fourth Spee-d operationrefer to Figure 6 Upon a further increase in thespeed of the vehicle the governor pressure in conduit 408 may move to avalue such that the piston 434 in the governor valve 410 will moveaxially to bring the fourth fhp jet D into fluid communication with theorifice 442 and to uncover the third progressive jet 431. The valve land5?;2 on plunger 435 is now moved suiiiciently far to the right to causethe conduit 478 to be blocked from uid communication with conduit 474.The conduit 478 is simultaneously exhausted through exhaust conduit 456.Thus, as pre- Fifth speed operation--refer `t Figure 7 As the vehiclespeed further increases, the piston element 434 in the governor valve410 shifts until the port E is in fluid communication with orifice 442and the fourth progressive jet 431 is uncovered. The valve land 512 willtherefore beshifted to the position shown thus again establishingcommunication between conduits 478 and 474 through the annular spacedefined by valve land 512 and another adjacent land shown at 542. Thesplit ratio shift valve is thus actuated as before to cause brake servoB1 to become energized and to cause the clutch servo C1 to be exhausted`Also,'the valve land 484 on the plunger 435 will be moved suiciently farto the right, as shown in Figure 7, to cause iluid communication betweenconduit 474 and aconduit 544, which extends to the main relay valve 498.The regulated fluid pressure thus transmitted to relay valve 498 causesthe valve element 504 to shift against the force exerted by spring 508until the shoulder 546 in the relay valve is contacted. This movement isaccompanied by a corresponding movement of the valve lands 518 and 520on element 582 thereby blocking oit' the conduit leading to brake servoB3 and establishing communication with the conduit leading to clutchservo The shifting motion of valve element 502 is effective to move theplunger 526 of the split ratio exhaust control valve 524. This enablesthe valve 524 to control the rate at which the clutch servo C1 isexhausted, as previously described.

Thus clutch servo C2 and brake servo B1 are both energized which resultsin fifth speed operation.

Sixth speed operation-refer to Figure 8 A further increase in vehiclespeed will cause the valve element 434 to shift until jet F becomesaligned with the orifices 442 and the fifth progressive jet isuncovered. The valve land 542 in plunger 435 will thereupon be shiftedto the position shown thus causing the conduit 478 to be blocked fromfluid communication with conduit 474. This again causes the split ratioshift .valve to move to the right hand position thus causing clutchservo C1 and brake servo B1 to be energized and exhausted, respectively,as previously described. The valve elements in the main relay valve 498remain in the same relative position thus causing the clutch servo C2 toremain energized.

Since clutch servos C1 and C2 are now engaged, the transmission isoperating in sixth speed.

Seventh speed` operation-refer to Figure 9 The position of the governorvalve for seventh speed operation is such that the jet G is in fluidcommunication with the orifices 442 and the sixth progressive jet 431 isuncovered. The corresponding movement of the plunger 435 is such thatthe valve lands 542 and an adjacent valve land 548 will provide forlluid communication between conduits 478 and 474 thereby causing theplunger 490 of the split ratio shift valve 488 to shift against theforce of spring 492 thus causing the brake servo B1 to be againenergized. Also, the movement of plunger 435 causes the valve land 484to establish fluid communication between conduit 474 and ar conduit 550,

which extends to one side of valve element 502 in the main relay Valve498. The regulated pressure thus transmitted to theV main relay valve498 causes the valve element 502 to shift until it contacts shoulder552. This movement causes the valve lands 518 and 520 to exhaust theclutch servo C2 and to establish communication between the conduitleading to brake servo B4 and the branch conduit 500.

The movement of valve element 502 also causes a corresponding movementof the plunger 526 in the split power exhaust control valve 524 which,as previously explained, retards the rate at which clutch servo C1 isexhausted.

Brake servos B1 and B4 are now energized which results in seventh speedoperation.

Eighth speed operation-refer to Figure 10 The piston 434 of vthegovernor control valve 410 moves completely to the right of orifice 442when the vehicle speed and the related governor pressure reach asuiciently high value, thus causing valve land 548 on plunger 435 toblock ol the conduit 478 from conduit 474. This again causes the splitratio shift valve to move thereby energizing clutch servo C1 andexhausting brake servo B1. The valve elements in the main relay valve498 do not change position.

Thus clutch servo C1 and brake servo B4 are thereby energized whichresults in eighthy speed operation.

During the above description of the operating sequence, it had beenassumed that the engine throttle position remained at a constantsetting. However, when the throttle position is changed, the throttlelinkage portion 454 is effective to axially shift a plunger 554 in thethrottle modulating valve 452. The plunger 554 is provided with a seriesof axially spaced metering orifices 556 through which the conduit 448communicates with another conduit 558 which supplies the modulatingvalve 452 with governor oil. The number of orifices 556 which mayfunction to transfer Huid from conduit 558 to conduit 448 will varydepending upon the axial position of plunger 554. The value of themodulated pressure in conduit 448 is therefore variable and is dependentupon the engine throttle position. It is thus seen that the shiftingsequence of the transmission is responsive to both speed and enginethrottle setting.

A manual lock-down valve is shown at 450 andl it comprises a manuallyactuated lever 560 which is connected to a slidable plunger 562, Aseries of passages 564 is adapted to be selectively blocked by theplunger 562 as the same moves from the position shown in Figure 3 to theleft. Upon movement to the left, the passages` 564 are p-rogressivelyopened to the exhaust port 566. A series of openings 568 is provided inthe portion 434 of the governor valve 410, as shown. A desired number ofpassages 564 may be opened to obtain a lockdown at the desired reductionratio. The piston 434 will be unable, except at an increased enginespeed, to move beyond the axial position at which the interior of thegovernor valve 418 communicates with one of the opened passages 564through the associated opening 568. The engine speed at which an upshiftwill occur, while operating at a selected range, will thus be higherthan that normally required during full throttle operation.

Referring again to the assembly view of Figure l, it will be noted thateach of the brake and clutch servos is actuated by means of fluidpressure which is adapted to act on'one side of the associated movablepiston elements. Suitable conduit means are provided for admitting theactuating uid to the uid working chamber of the respective servos aspreviously described. However, the clutch servos are unique in that eachof them is further provided with a second fluid chamber on the side ofthe associated friction element which is oppositely disposed withrespect to the Huid working chambers. This second 15 fluid chamber isadapted to receive lubricating uid under lubricating oil supplypressure.

It will be noted that the various clutch servos are adapted to rotatewith the associated planetary elements after being energized. The fluidpressure which woud normally be produced in the respective fluid workingchambers of the clutch servos due to the centrifugal pressure whichaccompanies this rotation tends to exert a holding force on the clutchfriction elements and to keep the clutch servo energized even after theexhaust port for the associated control valve has been opened.

The function of the respective second liuid chambers in the clutchservos is to provide a means for counteracting the centrifugal pressurebuild-up in the fluid working chambers with an oppositely directedpressure force. The response of the clutch servos to the movement of theassociated control valve elements will therefore be positive andimmediate.

This fluid balancing feature may be more particularly pointed out withreference to Figure l of the drawings. It may be noted, for example,that the clutch member 108 of the reverse clutch is provided with alubricating oil passage 580 which extends radially into an annularchamber 582 defined by the piston member 118 and an end plate 584 whichmay be held on the hub of the clutch member S by means of a snap ring orthe like. As the speed of the rotating clutch member 108 increases thereis a corresponding pressure build-up on both sides of the piston member118 in the working chamber defined by recess 116 and in the chamber 582which tend to oppose and to substantially balance each other. The spring134 may then cause the clutch friction elements 104 and 105 to becomedisengaged immediately upon exhausting the servo fluid working chamber.

Similar fluid balancing chambers may be provided for the forward clutchat 586, for the clutch 1 in the split power unit 12 at 588 and for theclutch 2 at S90.

Although a certain preferred embodiment of the invention has beenspecifically disclosed, it is understood that the invention is notlimited thereto since many variations will be readily apparent to thoseskilled in the art and the invention is to be given its broadestpossible interpretation within the terms of the following claims.

We claim:

l. In a power transmission, a power output shaft, a planetary gear unitcomprising a ring gear member, planet gears and a sun gear membermutually interengaged and coaxially disposed about an axis transverse tothe axis of said output shaft, a first carrier member for carrying saidplanet gears, one member of said planetary gear unit being adapted to bedriven by a source of input power and another member thereof beingadapted to be braked, a plurality of compounded planetary units havingthe component elements thereof coaxially disposed about said outputshaft, said compounded planetary units each comprising a sun gear memberand a ring gear member with planet gears engaged therebetween eachcompounded planetary unit having a carrier member for carrying theplanet gears thereof, a first pair of said compounded planetary unitshaving the sun gear members thereof connected to a common shaft means, asecond pair of said compounded planetary units having the sun gearmembers thereof connected to said power output shaft, drive meansinterconnecting a portion of said first named planetary gear unit withsaid shaft means and with a member of one unit of said second pair ofsaid compounded planetary units, one member of each unit of said secondpair of units being connected together and one member of each unit ofsaid first pair of units being connected together. the carrier member ofone unit of said first pair of compounded planetary units being drivablyconnected to said output shaft, means for selectively clutching togetherand braking other members of said compounded planetary units in sequenceto I6 progressively obtain varying torque multiplication ratios betweena power input source and said output shaft.

2. In a power transmission, a power output shaft, a planetary gear unitcomprising a `ring gear member, a sun gear member with planet gearsinterengaged therebetween and a carrier member for carrying said planetgears, said unit being coaxially disposed about an axis transverse tothe axis of said output shaft, one member of said planetary gear unitbeing adapted to be driven by a source of input power and another memberthereof being adapted to be braked, a plurality of compounded planetaryunits having the component elements thereof coaxially disposed aboutsaid output shaft and axially spaced thereon, said compounded planetaryunits each comprising a sun gear member, a ring gear member, planetgears engaged therebetween, and a carrier member for carrying saidlast-named planet gears, a first adjacent pair of said axially spacedplanetary units having the sun gear members thereof connected to acommon shaft means a second pair of said compounded planetary unitshaving the sun gear members thereof connected to said power outputshaft, drive means interconnecting said first named planetary gear unitwith said shaft means and with a member of one unit of said second pairof compounded planetary units, one member of each unit of said secondpair of units being connected together and one member of each unit ofsaid first pair of units being connected together, the carrier member ofone of said first adjacent pair of compounded planetary units beingdrivably connected to said output shaft, means for selectively clutchingtogeth'er members of one unit of said second pair of axially spacedplanetary units and brake means for selectively braking one member ofeach unit of said first pair of planetary units and for braking onemember of said second pair of planetary units.

3. In a power transmission, a power output shaft, a planetary gear unitcomprising a ring gear member, a sun gear member with planet gearsinterengaged therebetween and a carrier member for carrying said planetgears, said unit being coaxially disposed about an axis transverse tothe axis of said output shaft, one member of said planetary gear unitbeing adapted to be driven by a source of input power and another memberthereof being adapted to be braked, a plurality of compounded planetaryunits having the component elements thereof coaxially disposed aboutsaid output shaft and axially spaced thereon, said compounded planetaryunits each comprising a sun gear member and a ring gear member withplanet gears engaged therebetween, a carrier member for carrying saidlast-named planet gears, a rst adjacent pair of said axially spacedplanetary units having the sun gear members thereof connected to acommon shaft means, one member of each unit of said first pair ofplanetary units being interconnected drive means interconnecting saidfirst named planetary gear unit with said shaft means and with a carriermember of one -unit of said second pair of compounded planetary units,the ring gear of said one unit being connected to the carrier member ofthe other unit of said second pair of compounded planetary units, thecarrier member of one of said iirst adjacent pair of compoundedplanetary units being drivably connected to said output shaft, means forselectively clutching together members of one unit of said second pairof axially spaced planetary units, the sun gear members of said otherpair of axially spaced planetary units being connected to a commonportion of said output shaft and brake means for selectively braking onemember of each unit of said first pair of units and for braking onemember of said second pair of units.

4. In a power transmission, a power output shaft, a planetary gear withplanet gears unit comprising a ring gear member, a sun gear member withplanet gears interengaged therebetween and a carrier member for carryingsaid planet gears, said unit being coaxially disposed about an axistransverse to the axis of said output'shaft, one member of saidplanetary gearl unit being adapted to be driven by a source of inputpower and another member thereof being-adapted to be braked, a pluralityof compounded planetary units having the component elements thereofcoaxially disposed about said output shaft and axially spaced thereon,said compounded planetary units each comprising a sun gear member and aring gear member with planet gears engaged therebetween, a carriermember for carrying said last-named planet gears, a first adjacent pairof said axially spaced planetary units having the sun gear membersthereof connected to a common shaft means, drive means interconnectingsaid rst named planetary gear unit with said shaft means, the carriermember of one of said rst adjacent pair of compounded planetary unitsbeing drivably connected to said output shaft, the ring gear member ofsaid one unit of said first pair of units being connected to the carriermember of the other unit thereof the sun gear members of the other pairof axially spaced planetary units being connected to a common portion ofsaid output shaft, the carrier member of one unitof said other pair ofaxially spaced planetary units being drivably connected to said shaftmeans the ring gear of said one unit of said other adjacent pair ofaxially spaced planetary units being connected to the carrier member ofthe other unit thereof, and meansfor selectively clutching together andfor braking other members of said compounded planetary units in sequenceto obtain a series of torque ratios.

5. A power transmitting mechanism comprising in combination, atransmission housing, a simple planetary unit rotatably mounted in oneportion of said housing, said simple planetary unit including a ringgear and a sun gear with planet gears engaged therebetween, a carriermember for carrying said planet gears, a power output shaft rotatablymounted in another portion of said housing, a sleeve rotatablyjournalled about said output shaft, two pairs of compounded planetaryunits rotatably mounted about said output shaft each at axially spacedrelative positions, said compounded planetary units each comprising asun gear member and a ring gear member with interengaged planet gears, acarrier member for carrying said last-named planet gears, the sun gearmembers of one ,of said pairs of units and the carrier member of oneunit of the other pair of units being commonly secured to said sleeve,the sun gear members of said other pair of units being commonlyconnected to said output shaft, the carrier member of one unit of saidone pair off units being connected to said output shaft, the ring gearmember of said one unit of said one pair of units being connected to thecarrier of the other unit thereof, means for selectively clutchingtogether members of one unit of said other pair of unitsY and forbraking one member thereof to 'said housing, a right angle drive meansdrivably connecting the carrier member of said simple planetary unit tosaid sleeve and means for selectively braking the other members of saidone pair of planetary units, the other members of said other pair ofplanetary units being connected to each other.

6. A power transmitting mechanism as set forth in claim wherein saidright angle drive means includes a first gear drivably connected to thecarrier member of said simple planetary unit, a second gear rotatablyjournalled in a portion of said housing about said output shaft andengaged with said first gear, and means for selectively clutching saidsecond gear to said sleeve.

7. A power transmitting mechanism as set forth in claim 6 wherein saidright angle drive means further includes a third gear coaxially mountedabout said output shaft in juxtaposition with respect to said secondgear and interengaged with said first gear, and means for selectivelyclutching said third gear to said sleeve.

8. A power transmitting mechanism comprising a transmission housing, asimple planetary unit rotatably mounted in one portion of said housing,said simple planetary unit including a ring gear and a sun gear withinterconnecting planet gears, a carrier member drivably connected tosaid planet gears, a power output shaft rotatably mounted in anotherportion of said housing, a sleeve rotatably journalled about said outputshaft, two pairs ofl compounded planetary units rotatably mounted aboutsaid output shaft each at axially spaced relative positions, saidcompounded planetary units each comprising a sun gear and a ring gearwith interconnecting planet gears a carrier assembly drivably carryingsaid last-named planet gears, the sun gear of one of said pairs of unitsbeing commonly connected to said sleeve, the sun gears ofthe other ofsaid pair of units being commonly connected to said output shaft, thecarrier assembly of one unit of said one pair of units being fixed tosaid output shaft, the carrier assembly of one unit of said other pairof units being xed to said sleeve, the ring gear of said one unit ofsaid one pair of units being drivably connected to the carrier assemblyof the other unit of said one pair of units, the ring gear of said oneunit of said other pair of units being drivably connected to the carrierassembly of the other unit of said other pair of units, means forselectively clutching the ring gear of the other unit of said other pairof units to said output shaft and for braking the same to said housing,a right angle drive means interconnecting the carrier assembly of saidsimple planetary unit to said sleeve, said right angle drive meansincluding a rst gear drivably secured to the carrierassembly of saidsimple planetary unit, a second gear rotatably journalled in said otherp01'- tion of said housing about said output shaft and interengaged withsaid first gear, means for selectively clutching said second gear tosaid sleeve, and means for selectively braking each of the ring gears ofthe said one pair of units to said housing.

9. A power transmitting mechanism comprising a transmission housing, asimple planetary unit rotatably mounted in one portion of said housing,said simple planetary unit including a ring gear and a sun gear withinterconnecting planet gears, a carrier member drivably connected tosaid planet gears, a power output shaft rotatably mounted in anotherportion of said housing, a sleeve rotatably journalled about said outputshaft, two pairs of compounded planetary units rotatably mounted aboutsaid output shaft each at axially spaced relative positions, saidcompounded planetary units each comprising a sun gear and a ring gearwith interconnecting planet gears a carrier assembly drivably carryingsaid last-named planet gears, the sun gear of one of said pairs of unitsbeing commonly connected to said sleeve, the sun gears of the other ofsaid pairs of units being commonly connected to said output shaft, thecarrier assembly of one unit of said one pair of units being xed to saidoutput shaft, the carrier assembly of one unit of said other pair ofunits being fixed to said sleeve, the ring gear of said one unit of saidone pair of units being drivably connected to the carrier assembly ofthe other unit of said one pair of units, the ring gear of said one unitof said other pair of units being drivably connected to the carrierassembly of the other unit of said other pair of units, means forselectively clutching the ring gear of one of said other pair of unitsto said output shaft and for braking the same to said housing, a rightangle drive means interconnecting the carrier assembly of said simpleplanetary unit to said sleeve, said right angle drive means including afirst gear drivably secured to the carrier member of said simpleplanetary unit, a second gear rotatably journalled in said other portionof said housing about said output shaft and interengaged ywith saidfirst gear,

v means for selectively clutching said second gear to said spectively,said clutching and braking means for said compounded planetary unitsbeing adapted to be energized in an operative sequence while said meansfor clutching said second gear to said sleeve remains energized therebyproviding a substantially uniform progressive series of torquemultiplication gear ratios between said power input source and saidoutput shaft.

10. A power transmitting mechanism as set forth in claim 9 wherein saidclutching and braking means for said simple planetary unit are adaptedto be alternately energized in sequence during the operation of eachindividual clutch and brake means for the pairs of compounded planetaryunits thereby sequentially compounding the torque reduction ratios ofsaid simple planetary unit with each of the plurality of reductionratios of said compounded planetary units.

1l. A power transmitting mechanism as set forth in claim 10 wherein saidright angle drive means further includes a third gear rotatablyjournalled in said other portion of said housing about said output shaftin juxtaposition with respect to said second gear, and means forselectively clutching said third gear to the carrier member of said oneunit of said other pair of units alternately with respect to theoperation of said means for clutching said second gear to said sleeve.

12. A power transmitting mechanism as set forth in claim 8 wherein saidright angle drive further includes a third gear rotatably journalled insaid other portion of said housing about said output shaft injuxtaposition with respect to said second gear, and means forselectively clutching said third gear to the carrier member of said oneunit of said other pair of units alternately with respect to theoperation of said means for clutching said second gear to said sleeve.

13. In a power transmitting mechanism, a housing; two pairs ofcompounded planetary units mounted within said housing, each unit ofsaid pairs of units comprising a ring gear member, a sun gear member, acarrier member and planet gears carried by said carrier member andinterengaged with said sun and ring gear member; a power output shaft, asleeve coaxially mounted about said shaft, each of said units beingcoaxially disposed with respect to each other about said output shaft,the sun gear members of one of said pairs of units being connected tosaid sleeve, the sun gear members of the other of said pairs of unitsbeing connected to said output shaft, means for selectively clutchingtogether members of one unit of said other pair of units and for brakingone member thereof to said housing, the carrier member of one unit ofsaid one pair of units being connected to said output shaft, the ringgear member of said last-named unit being coupled to the carrier memberof the other unit of said one pair of units, means for deliveringdriving power to said sleeve and to the carrier member of the other unitof said other pair of units, the ring gear member of said other unit ofsaid other pair of units being connected to the carrier member of saidone unit of said other pairs of units, and means for selectively brakingthe ring gear members of said one pair of units to said housing.

14. A transmission as set forth in claim 13 wherein said means fordelivering driving power includes an input shaft, a right angle drivebetween said input and output shafts, and a simple planetary gear unitoperatively connecting said input shaft to a power source.

15. In a power transmitting mechanism, a housing; two pairs ofcompounded planetary units mounted within said housing, each unit ofsaid pairs of units having components comprising a ring gear, a sungear, a carrier and planet gears carried by said carrier andinterengaged with said sun and ring gears; a power output shaft, asleeve coaxially mounted with respect to said shaft, each of said unitsbeing coaxially disposed with respect to said output shaft, the sungears of one of said pairs of units being fixed to said sleeve, the sungears of the other of said pairs of units being fixed to' said outputshaft, means for selectively clutching together components of said otherpair of units and for braking one component of the same to said housing,the carrier of one unit of said one pair of units being connected tosaid output shaft, the ring gear `of said last-named unit being coupledto the carrier of the other unit of said one pair of units, the ringgear of one unit of said other pair of units being connected to thecarrier of the other unit of said other pair of units, means fordelivering driving power to said sleeve and to the carrier of said oneunit of said other pair of units, and means for selectively braking eachof the ring gears of said one pair of units to said housing.

16. In a power transmitting mechanism, a housing; two pairs ofcompounded planetary units mounted within said housing, each unit ofsaid pairs having components comprising a ring gear, a sun gear, acarrier and planet gears carried by said carrier and interengaged withsaid sun and ring gears; a power output shaft, a sleeve axially mountedwith respect to said shaft, each of said units being axially disposedwith respect to said output shaft, the sun gears of one of said pairs ofunits being fixed to said sleeve, the sun gears of the other of saidpairs of units being fixed to said output shaft, means for selectivelyclutching together components of said other pair of units and forbraking one component of the same to said housing, the carrier of oneunit of said one pair of units being connected to said output shaft, thering gear of said last-named unit being coupled to the carrier of theother unit of said one pair of units, the ring gear of one unit of saidother pair of units being connected to the carrier of the other unit ofsaid other pair of units, means for delivering driving power to saidsleeve, the carrier of said one unit of said other pair of units beingconnected to said sleeve, and means for selectively braking each of thering gears of said one pair of units to said housing.

17. In a power transmitting mechanism, a housing; two pairs ofcompounded planetary units mounted within said housing, each unit ofsaid pairs of units having components comprising a ring gear, a sungear, a carrier and planet gears carried by said carrier andinterengaged with said sun and ring gears; a power output shaft, asleeve coaxially mounted with respect to said shaft, each of said unitsbeing coaxially disposed with respect to said output shaft, the sungears of one of said pairs of units being connected to said sleeve, thesun gears of the other of said pairs of units being connected to saidoutput shaft, means for selectively clutching together components of oneunit of said other pair of units and for braking one component of thesame to said housing, the carrier of one unit of said one pair of unitsbeing Connected to said output shaft, the ring gear of said last-namedunit being coupled to the carrier of the other unit of said one pair ofunits. means for delivering driving power to said sleeve and to thecarrier of the other unit of said other pair of units, the ring gear ofsaid other unit of said other pair of units being connected to thecarrier of said one unit of said other pair of units, means forselectively braking the ring gears of said one pair of units to saidhousing, said power delivery means comprising a power input shaft havingan axis substantially perpendicular to the axis of said output shaft,and a right angle drive means for drivably connecting said input shaftand said sleeve.

18. In a power transmitting mechanism, a housing; two pairs ofcompounded planetary units mounted within said housing, each unit ofsaid pairs of units comprising a ring gear, a sun gear, a carrier andplanet gears carried by said carrier and interengaged with said sun andring gears; a power output shaft, a sleeve concentrically mounted aboutsaid shaft, each of said units being coaxially disposed with respect toeach other about said output shaft, the sun gears of one of said pairsof units being fixed to said sleeve, the sun gears of the other of saidpairs of units being fixed to said output shaft, means for selectivelyclutching the ring gear of one unit of said

